-
-static int ssl_scan_serverhello_tlsext(SSL *s, PACKET *pkt, int *al)
-{
- RAW_EXTENSION *extensions = NULL;
- PACKET extpkt;
-
-#ifndef OPENSSL_NO_NEXTPROTONEG
- s->s3->next_proto_neg_seen = 0;
-#endif
- s->tlsext_ticket_expected = 0;
-
- OPENSSL_free(s->s3->alpn_selected);
- s->s3->alpn_selected = NULL;
-
- s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC;
-
- s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS;
-
- if (!PACKET_as_length_prefixed_2(pkt, &extpkt)) {
- /* Extensions block may be completely absent in SSLv3 */
- if (s->version != SSL3_VERSION || PACKET_remaining(pkt) != 0) {
- *al = SSL_AD_DECODE_ERROR;
- SSLerr(SSL_F_SSL_SCAN_SERVERHELLO_TLSEXT, SSL_R_BAD_LENGTH);
- return 0;
- }
- PACKET_null_init(&extpkt);
- }
-
- /*
- * TODO(TLS1.3): We give multiple contexts for now until we're ready to
- * give something more specific
- */
-
- if (!tls_collect_extensions(s, &extpkt, EXT_TLS1_2_SERVER_HELLO
- | EXT_TLS1_3_SERVER_HELLO
- | EXT_TLS1_3_ENCRYPTED_EXTENSIONS
- | EXT_TLS1_3_CERTIFICATE,
- &extensions, al))
- return 0;
-
- /*
- * Determine if we need to see RI. Strictly speaking if we want to avoid
- * an attack we should *always* see RI even on initial server hello
- * because the client doesn't see any renegotiation during an attack.
- * However this would mean we could not connect to any server which
- * doesn't support RI so for the immediate future tolerate RI absence
- */
- if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT)
- && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION)
- && !extensions[TLSEXT_IDX_renegotiate].present) {
- *al = SSL_AD_HANDSHAKE_FAILURE;
- SSLerr(SSL_F_SSL_SCAN_SERVERHELLO_TLSEXT,
- SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED);
- return 0;
- }
-
- if (!tls_parse_all_extensions(s, EXT_TLS1_2_SERVER_HELLO
- | EXT_TLS1_3_SERVER_HELLO
- | EXT_TLS1_3_ENCRYPTED_EXTENSIONS
- | EXT_TLS1_3_CERTIFICATE,
- extensions,al))
- return 0;
-
- if (s->hit) {
- /*
- * Check extended master secret extension is consistent with
- * original session.
- */
- if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) !=
- !(s->session->flags & SSL_SESS_FLAG_EXTMS)) {
- *al = SSL_AD_HANDSHAKE_FAILURE;
- SSLerr(SSL_F_SSL_SCAN_SERVERHELLO_TLSEXT, SSL_R_INCONSISTENT_EXTMS);
- return 0;
- }
- }
-
- return 1;
-}
-
-static int ssl_check_serverhello_tlsext(SSL *s)
-{
- int ret = SSL_TLSEXT_ERR_NOACK;
- int al = SSL_AD_UNRECOGNIZED_NAME;
-
-#ifndef OPENSSL_NO_EC
- /*
- * If we are client and using an elliptic curve cryptography cipher
- * suite, then if server returns an EC point formats lists extension it
- * must contain uncompressed.
- */
- unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
- unsigned long alg_a = s->s3->tmp.new_cipher->algorithm_auth;
- if ((s->tlsext_ecpointformatlist != NULL)
- && (s->tlsext_ecpointformatlist_length > 0)
- && (s->session->tlsext_ecpointformatlist != NULL)
- && (s->session->tlsext_ecpointformatlist_length > 0)
- && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) {
- /* we are using an ECC cipher */
- size_t i;
- unsigned char *list;
- int found_uncompressed = 0;
- list = s->session->tlsext_ecpointformatlist;
- for (i = 0; i < s->session->tlsext_ecpointformatlist_length; i++) {
- if (*(list++) == TLSEXT_ECPOINTFORMAT_uncompressed) {
- found_uncompressed = 1;
- break;
- }
- }
- if (!found_uncompressed) {
- SSLerr(SSL_F_SSL_CHECK_SERVERHELLO_TLSEXT,
- SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST);
- return -1;
- }
- }
- ret = SSL_TLSEXT_ERR_OK;
-#endif /* OPENSSL_NO_EC */
-
- if (s->ctx != NULL && s->ctx->tlsext_servername_callback != 0)
- ret =
- s->ctx->tlsext_servername_callback(s, &al,
- s->ctx->tlsext_servername_arg);
- else if (s->initial_ctx != NULL
- && s->initial_ctx->tlsext_servername_callback != 0)
- ret =
- s->initial_ctx->tlsext_servername_callback(s, &al,
- s->
- initial_ctx->tlsext_servername_arg);
-
- /*
- * Ensure we get sensible values passed to tlsext_status_cb in the event
- * that we don't receive a status message
- */
- OPENSSL_free(s->tlsext_ocsp_resp);
- s->tlsext_ocsp_resp = NULL;
- s->tlsext_ocsp_resplen = 0;
-
- switch (ret) {
- case SSL_TLSEXT_ERR_ALERT_FATAL:
- ssl3_send_alert(s, SSL3_AL_FATAL, al);
- return -1;
-
- case SSL_TLSEXT_ERR_ALERT_WARNING:
- ssl3_send_alert(s, SSL3_AL_WARNING, al);
- return 1;
-
- case SSL_TLSEXT_ERR_NOACK:
- s->servername_done = 0;
- default:
- return 1;
- }
-}
-
-int ssl_parse_serverhello_tlsext(SSL *s, PACKET *pkt)
-{
- int al = -1;
- if (s->version < SSL3_VERSION)
- return 1;
- if (ssl_scan_serverhello_tlsext(s, pkt, &al) <= 0) {
- ssl3_send_alert(s, SSL3_AL_FATAL, al);
- return 0;
- }
-
- if (ssl_check_serverhello_tlsext(s) <= 0) {
- SSLerr(SSL_F_SSL_PARSE_SERVERHELLO_TLSEXT, SSL_R_SERVERHELLO_TLSEXT);
- return 0;
- }
- return 1;
-}